The present invention relates to novel amidosilane compounds and more particularly the present invention relates to novel silyl-amide compounds which have difunctional amido groups.
Silyl-amide compounds have been developed and patented as can be seen in the disclosure of Klebe, U.S. Pat. No. 3,488,371. Such silyl-amide compounds are also disclosed in Golitz, U.S. Pat. No. 3,417,047 which discloses the use of acetamido functional silanes as cross-linking agents to form one-component room temperature vulcanizable silicone rubber compositions. It was noted in that patent that there had to be at least three acetamido functional groups in the silane for the silane siloxane to function as a cross-linking agent.
Recently in the case of difunctional silyl-amide and siloxanyl amide compounds there has been developed a novel use for such compounds. An example of the disclosure of such silyl-amide compounds is, for instance, to be found in Klebe, U.S. Pat. No. 3,488,371. This patent deals with the synthesis and development of difunctional acetamido and silanes and siloxanes. The disclosures of Toporcer, U.S. Pat. Nos. 3,776,934 and 3,776,933 should be noted in this regard. The U.S. Pat. No. 3,776,934 states that the Klebe patent disclosed dimethyl-bis(N-methyl-acetamido)silanes in methylphenyl-bis(N-methylacetamido)silanes and diphenyl-bis(N-methylacetamido)silanes. It was the alleged invention of this patent to develop methylvinyl-bis(N-methylacetamido)silanes. However, note the disclosure of Klebe, U.S. Pat. No. 3,488,371, which at the bottom of Column 2 and at the top of Column 3 of the patent discloses the purported invention of U.S. Pat. No. 3,776,934.
Irrespective of the above, patents such as U.S. Pat. No. 4,020,044 appreciated the use of, for instance, methylvinylacetamido silanes as chain extenders for silanol-terminated diorganopolysiloxanes. Other patents such as U.S. Pat. No. 3,817,909 disclose the use of the various methylphenyl and methylvinyl and dimethylacetamido functional silanes which are difunctional in the acetamido groups as couplers to form one-component RTV compositions of extremely low modulus.
Briefly, these compositons function as follows: The difunctional acetamido silanes are added to the silanol polymer along with other fillers and additives and once added result in the difunctional acetamido silanes reacting with the silanol groups of linear silanol polymers to remit in acetamido silyl terminal groups. There is also incorporated into such a composition a small amount of aminoxy functional cyclopolysiloxanes as cross-linking agents. The composition is packaged in a single package in a substantially anhydrous state. When it is desired to cure the composition, the composition is exposed to moisture which results in the hydrolysis of the aminoxy groups and cross-linking and coupling to long chain higher molecular weight linear diorganopolymers so as to result in an elastomer. However, because of the high or the long chain polymer resulting from the coupling reaction the composition has an extremely low modulus as exhibited by elongations of 800 to 1,600 percent and a small but appreciable tensile strength. Such compositions have been found to have good unprimed adhesion properties and as such have been found to be useful as sealants.
One purpose of such sealants, for instance, has been to seal the joints in concrete pavement so as to prevent moisture from entering beneath the joint that is formed between the concrete slabs and freezing and expanding thus causing up-heaval of the concrete block.
Accordingly, it was highly desirable to find a more reactive difunctional acetamido coupler that is more reactive than that of most of the prior difunctional acetamido silanes and siloxanes.
In another vein, it is disclosed in Toporcer, U.S. Pat. No. 3,776,933, that the amido silanes can be produced by reacting a dichlorohydridosilane with the appropriate intermediate to produce the diorganodichlorosilane. The resulting diorganodichlorosilane can then be reacted with a metal salt of an organic amide so as to replace the chlorine groups in the dichlorosilane with amide groups and give off an alkaline metal salt as the by-product. The resulting salt can then be filtered off and the solvent removed to result in the desired product in substantial yield. The above process was utilized with advantage to produce the desired difunctional amido silane in substantial yield. Nevertheless, it was undesirable in that it necessitated the handling of an alkali metal solid which is undesirable because it might cause a fire. Accordingly, it was highly desirable to modify this process to produce novel difunctional acetamido silanes which were more reactive than the prior art difunctional acetamido silanes even though the process was not as advantageous as would be desired. In addition, it was highly desirable to modify the prior art processes both utilizing alkali metal and not utilizing an alkali metal to product novel difunctional acetamido silanes which were more reactive than the prior art difunctional acetamido silanes.
Accordingly, it was one object of the present invention to provide novel difunctional acetamido silanes.
It is another object of the present invention to provide a novel process for producing novel difunctional acetamido silane compounds.
It is an additional object of the present invention to provide novel difunctional acetamido silanes which can function as couplers in the production of extremely low modulus one-component RTV systems.
These and other objects of the present invention are accomplished by means of the disclosure set forth hereinbelow.